Multi-speed transmission

Abstract

A transmission is provided having an input member, an output member, four planetary gear sets, a plurality of coupling members and a plurality of torque transmitting devices. Each of the planetary gear sets includes first, second and third members. The torque transmitting devices may include clutches and at least one brake. The torque transmitting mechanisms are selectively engageable in combinations of at least two to establish at least eight forward speed ratios and at least one reverse speed ratio between the input member and the output member.

1. A transmission comprising:
 an input member; 
 an output member; 
 first, second, third and fourth planetary gear sets each having first, second and third members; 
 a plurality of interconnecting members each continuously interconnecting one of the first, second, and third members of the planetary gear sets with another one of the first members, second members, and third members of the planetary gear sets and a stationary member; 
 a first torque transmitting mechanism selectively engageable to interconnect the second member of the fourth planetary gear set with the stationary element; 
 a second torque transmitting mechanism selectively engageable to interconnect the second member of the fourth planetary gear set with the second member of the first planetary gear set; 
 a third torque transmitting mechanism selectively engageable to interconnect the second member of the fourth planetary gear set with the third member of the second planetary gear set; 
 a fourth torque transmitting mechanism selectively engageable to interconnect at least one of the first member of the fourth planetary gear set and the input member with the third member of the second planetary gear set; and 
 a fifth torque transmitting mechanism selectively engageable to interconnect at least one of the second member of the third planetary gear set and the output member with the second member of the first planetary gear set, and 
 wherein the torque transmitting mechanisms are selectively engageable in combinations of at least two to establish at least eight forward speed ratios and at least one reverse speed ratio between the input member and the output member. 
 
     
     
       2. The transmission of  claim 1  wherein the first members are sun gears, the second members are carrier members, and the third members are ring gears. 
     
     
       3. The transmission of  claim 1  wherein one of the torque transmitting mechanisms is a brake and four of the torque transmitting mechanisms are clutches. 
     
     
       4. The transmission of  claim 1  wherein the stationary element is a transmission housing. 
     
     
       5. The transmission of  claim 1  wherein the input member is continuously interconnected with the first member of the fourth planetary gear set and wherein the output member is continuously interconnected with the second member of the third planetary gear set. 
     
     
       6. The transmission of  claim 1  wherein a first of the plurality of interconnecting members continuously interconnects the third member of the fourth planetary gear set with the second member of the second planetary gear set. 
     
     
       7. The transmission of  claim 6  wherein a second of the plurality of interconnecting members continuously interconnects the first member of the third planetary gear set with the first member of the second planetary gear set. 
     
     
       8. The transmission of  claim 7  wherein a third of the plurality of interconnecting members continuously interconnects the first member of the second planetary gear set with the third member of the first planetary gear set. 
     
     
       9. The transmission of  claim 8  wherein a fourth of the plurality of interconnecting members continuously interconnects the third member of the third planetary gear set with the second member of the second planetary gear set. 
     
     
       10. The transmission of  claim 9  wherein a fifth of the plurality of interconnecting members continuously interconnects the first member of the first planetary gear set with a stationary element. 
     
     
       11. A transmission comprising:
 an input member; 
 an output member; 
 first, second, third and fourth planetary gear sets each having first, second and third members; 
 a first interconnecting member continuously interconnecting the third member of the fourth planetary gear set with the second member of the second planetary gear set; 
 a second interconnecting member continuously interconnecting the first member of the third planetary gear set with the first member of the second planetary gear set; 
 a third interconnecting member continuously interconnecting the first member of the second planetary gear set with the third member of the first planetary gear set; 
 a fourth interconnecting member continuously interconnecting the third member of the third planetary gear set with the second member of the second planetary gear set; 
 a fifth interconnecting member continuously interconnecting the first member of the first planetary gear set with a stationary element; 
 a first torque transmitting mechanism selectively engageable to interconnect the second member of the fourth planetary gear set with the stationary element; 
 a second torque transmitting mechanism selectively engageable to interconnect the second member of the fourth planetary gear set with the second member of the first planetary gear set; 
 a third torque transmitting mechanism selectively engageable to interconnect the second member of the fourth planetary gear set with the third member of the second planetary gear set; 
 a fourth torque transmitting mechanism selectively engageable to interconnect at least one of the first member of the fourth planetary gear set and the input member with the third member of the second planetary gear set; and 
 a fifth torque transmitting mechanism selectively engageable to interconnect at least one of the second member of the third planetary gear set and the output member with the second member of the first planetary gear set, and 
 wherein the torque transmitting mechanisms are selectively engageable in combinations of at least two to establish at least eight forward speed ratios and at least one reverse speed ratio between the input member and the output member. 
 
     
     
       12. The transmission of  claim 11  wherein the first members are sun gears, the second members are carrier members, and the third members are ring gears. 
     
     
       13. The transmission of  claim 11  wherein the stationary element is a transmission housing. 
     
     
       14. The transmission of  claim 11  wherein the input member is continuously interconnected with the first member of the fourth planetary gear set and wherein the output member is continuously interconnected with the second member of the third planetary gear set. 
     
     
       15. A transmission comprising:
 an input member; 
 an output member; 
 first, second, third and fourth planetary gear sets each having a sun gear, a carrier member, and a ring gear; 
 a first interconnecting member continuously interconnecting the ring gear of the fourth planetary gear set with the carrier member of the second planetary gear set; 
 a second interconnecting member continuously interconnecting the sun gear of the third planetary gear set with the sun gear of the second planetary gear set; 
 a third interconnecting member continuously interconnecting the sun gear of the second planetary gear set with the ring gear of the first planetary gear set; 
 a fourth interconnecting member continuously interconnecting the ring gear of the third planetary gear set with the carrier member of the second planetary gear set; 
 a fifth interconnecting member continuously interconnecting the sun gear of the first planetary gear set with a stationary element; 
 a first torque transmitting mechanism selectively engageable to interconnect the carrier member of the fourth planetary gear set with the stationary element; 
 a second torque transmitting mechanism selectively engageable to interconnect the carrier member of the fourth planetary gear set with the carrier member of the first planetary gear set; 
 a third torque transmitting mechanism selectively engageable to interconnect the carrier member of the fourth planetary gear set with the ring gear of the second planetary gear set; 
 a fourth torque transmitting mechanism selectively engageable to interconnect at least one of the sun gear of the fourth planetary gear set and the input member with the ring gear of the second planetary gear set; and 
 a fifth torque transmitting mechanism selectively engageable to interconnect at least one of the carrier member of the third planetary gear set and the output member with the carrier member of the first planetary gear set, and 
 wherein the torque transmitting mechanisms are selectively engageable in combinations of at least two to establish at least eight forward speed ratios and at least one reverse speed ratio between the input member and the output member. 
 
     
     
       16. The transmission of  claim 15  wherein the stationary element is a transmission housing. 
     
     
       17. The transmission of  claim 15  wherein the input member is continuously interconnected with the sun gear of the fourth planetary gear set and wherein the output member is continuously interconnected with the carrier member of the third planetary gear set.